Figure 1.

Experimental design and results from experiment 1 (left panels) and experiment 2 (right panels). (a,b) Both experiments were divided into an observational stage and a direct test stage. Note that in experiment 2, the observational extinction stage was preceded by a direct acquisition stage (see the electronic supplementary material, figure S1). (c,d) Mean CR (expressed as CS⁺/CS⁻ SCR difference) as a function of in- and out-group demonstrator displayed for the observational and direct test stages separately for experiment 1 (left) and experiment 2 (right). Given the significant CS × time × group interaction during the test stage in experiment 1 (but not in experiment 2), data are plotted separately for the early and late stage of the direct test in experiment 1. Error bars indicate standard error of the mean. Asterisks indicate statistically significant differences (p < 0.05).